A supporting frame structure for a vehicle door includes at least one forward frame section as viewed in the length direction of the vehicle, a rear frame section, and at least one upper frame section forming together a modular support unit. The door also includes a device for opening and closing a window as well as guide members for guiding the window when it is raised and lowered. Further door elements such as hinges, a door lock and respective operating components for the lock also form part of such modular units. The device for lifting and lowering the window may, for example, be a rope or cable lifter or a lazy-tong lifter.
The features for guiding the window movements and for simplifying the entire structure still leave room for improvement, especially with regard to the weight of the entire unit and its assembly.